Attachment manager for multi-processing

[s3rj1k]

refs:

• https://gerrit.mcp.mirantis.com/q/I00469e520053c14ed2954b5ed2ad6a56a1501054

"Upstream attachment manager does not work for several workers or several processes on the same host"

[s3rj1k]

https://gerrit.mcp.mirantis.com/q/branch:+mcp/caracal+project:packaging/sources/glance_store+file:glance_store/common/attachments_for_processes.py+is:merged

There are more related commits without a specific list in place

[s3rj1k]

I guess you could try to repro it on a multi-node devstack by:

    setting up glance on cinder
    set up several workers for glance
    enable cinder-volume only on compute node
        so that a remote iscsi mount is used for sure
    upload image to glance - it will be stored in lvm on compute
    try downloading this very image several times in parallel, with some time shift
        it will quite probably fail (may be need several tries), because first worker will detach the volume sooner than the other worker finishes serving data from that volume

[s3rj1k]

Current status: unable to gather proper list of changes, have rejects when trying to apply provided list of patches on top of glance_store -> stable/2024.1

[s3rj1k]

https://gerrit.mcp.mirantis.com/c/packaging/sources/glance_store/+/207868
https://gerrit.mcp.mirantis.com/q/project:packaging/sources/glance_store+branch:mcp/caracal+is:merged

[s3rj1k]

Corrected changes: https://gerrit.mcp.mirantis.com/q/topic:%22multi-proccess-attach%22+branch:master+project:packaging/sources/glance_store

[s3rj1k]

There are two sets of CRs that try to fix similar problem
https://bugs.launchpad.net/glance-store/+bug/1965679
https://review.opendev.org/q/topic:%22bug/1965679%22
(seems like none have Specs 🌝 )